<script src="../../dist/vue.min.js"></script>
<script>
  const { ref, computed, createApp } = Vue

  // math helper...
  function valueToPoint(value, index, total) {
    var x = 0
    var y = -value * 0.8
    var angle = ((Math.PI * 2) / total) * index
    var cos = Math.cos(angle)
    var sin = Math.sin(angle)
    var tx = x * cos - y * sin + 100
    var ty = x * sin + y * cos + 100
    return {
      x: tx,
      y: ty
    }
  }

  const AxisLabel = {
    template: '<text :x="point.x" :y="point.y">{{stat.label}}</text>',
    props: {
      stat: Object,
      index: Number,
      total: Number
    },
    setup(props) {
      return {
        point: computed(() =>
          valueToPoint(+props.stat.value + 10, props.index, props.total)
        )
      }
    }
  }
</script>

<!-- template for the polygraph component. -->
<script type="text/x-template" id="polygraph-template">
  <g>
    <polygon :points="points"></polygon>
    <circle cx="100" cy="100" r="80"></circle>
    <axis-label
      v-for="(stat, index) in stats"
      :stat="stat"
      :index="index"
      :total="stats.length">
    </axis-label>
  </g>
</script>

<script>
  const Polygraph = {
    props: ['stats'],
    template: '#polygraph-template',
    setup(props) {
      return {
        points: computed(() => {
          const total = props.stats.length
          return props.stats
            .map((stat, i) => {
              const point = valueToPoint(stat.value, i, total)
              return point.x + ',' + point.y
            })
            .join(' ')
        })
      }
    },
    components: {
      AxisLabel
    }
  }
</script>

<!-- demo root element -->
<div id="demo">
  <!-- Use the polygraph component -->
  <svg width="200" height="200">
    <polygraph :stats="stats"></polygraph>
  </svg>
  <!-- controls -->
  <div v-for="stat in stats">
    <label>{{stat.label}}</label>
    <input type="range" v-model="stat.value" min="0" max="100" />
    <span>{{stat.value}}</span>
    <button @click="remove(stat)" class="remove">X</button>
  </div>
  <form id="add">
    <input name="newlabel" v-model="newLabel" />
    <button @click="add">Add a Stat</button>
  </form>
  <pre id="raw">{{ stats }}</pre>
</div>

<script>
  const globalStats = [
    { label: 'A', value: 100 },
    { label: 'B', value: 100 },
    { label: 'C', value: 100 },
    { label: 'D', value: 100 },
    { label: 'E', value: 100 },
    { label: 'F', value: 100 }
  ]

  new Vue({
    components: {
      Polygraph
    },
    setup() {
      const newLabel = ref('')
      const stats = ref(globalStats)

      function add(e) {
        e.preventDefault()
        if (!newLabel.value) return
        stats.value.push({
          label: newLabel.value,
          value: 100
        })
        newLabel.value = ''
      }

      function remove(stat) {
        if (stats.value.length > 3) {
          stats.value.splice(stats.value.indexOf(stat), 1)
        } else {
          alert("Can't delete more!")
        }
      }

      return {
        newLabel,
        stats,
        add,
        remove
      }
    }
  }).$mount('#demo')
</script>

<style>
  body {
    font-family: Helvetica Neue, Arial, sans-serif;
  }

  polygon {
    fill: #42b983;
    opacity: 0.75;
  }

  circle {
    fill: transparent;
    stroke: #999;
  }

  text {
    font-family: Helvetica Neue, Arial, sans-serif;
    font-size: 10px;
    fill: #666;
  }

  label {
    display: inline-block;
    margin-left: 10px;
    width: 20px;
  }

  #raw {
    position: absolute;
    top: 0;
    left: 300px;
  }
</style>
